package com.lzh.java;

/**
 * @author liuzhihao
 * @create 2021-02-17 10:32
 */

import org.junit.Test;

import java.time.*;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
import java.time.temporal.TemporalAccessor;
import java.util.Date;

/**
 * jdk 8中日期时间API的测试
 */
public class JDK8DatetimeTest {

    @Test
    public void testDate(){
        //偏移量
        Date date = new Date(2021 - 1900,2-1,17);
        System.out.println(date);
    }

    /**
     * LocalDate,LocalTime,LocalDatTime的使用
     *
     * 说明：
     *  1.LocalDateTime相较于LocalDate\LocalTime,使用频率要高
     *  2.类似于Calendar
     */
    @Test
    public void test1(){
        //now():获取当前的日期、时间、日期+时间
        LocalDate localDate = LocalDate.now();
        LocalTime localTime = LocalTime.now();
        LocalDateTime localDateTime = LocalDateTime.now();

        System.out.println(localDate);
        System.out.println(localTime);
        System.out.println(localDateTime);

        //of():设置指定的年、月、日、时、分、秒。没有偏移量
        LocalDateTime localDateTime1 = LocalDateTime.of(2021, 2, 17, 10, 52, 59, 43);
        System.out.println(localDateTime1);

        //getXxx():
        //获取相关属性
        System.out.println(localDateTime.getDayOfMonth());
        System.out.println(localDateTime.getDayOfWeek());
        System.out.println(localDateTime.getMonth());
        System.out.println(localDateTime.getMonthValue());
        System.out.println(localDateTime.getMinute());

        //体现不可变性
        //withXxx():设置相关属性
        LocalDate localDate1 = localDate.withDayOfMonth(22);
        System.out.println(localDate);
        System.out.println(localDate1);

        LocalDateTime localDateTime2 = localDateTime.withHour(4);
        System.out.println(localDateTime);
        System.out.println(localDateTime2);

        //不可变性
        LocalDateTime localDateTime3 = localDateTime.plusMonths(3);
        System.out.println(localDateTime);
        System.out.println(localDateTime3);

        LocalDateTime localDateTime4 = localDateTime.minusDays(6);
        System.out.println(localDateTime);
        System.out.println(localDateTime4);
    }

    /**
     * Instant的使用
     * 类似于java.util.Date类
     */
    @Test
    public void test2(){
        //now():获取本初子午线对应的标准时间
        Instant instant = Instant.now();
        System.out.println(instant);

        //添加时间的偏移量
        OffsetDateTime offsetDateTime = instant.atOffset(ZoneOffset.ofHours(8));
        System.out.println(offsetDateTime);

        //toEpochMilli():获取对应的毫秒数（自1970年1月1日0时0分0秒（UTC）开始的毫秒数） -->Date类的getTime()
        long toEpochMilli = instant.toEpochMilli();
        System.out.println(toEpochMilli);

        //ofEpochMilli():通过给定的毫秒数，获取Instant实例 --->Date(long millis)
        Instant instant1 = Instant.ofEpochMilli(1613531564587L);
        System.out.println(instant1);
    }

    /**
     * DateTimeFormatter:格式化或解析日期、时间
     * 类似于SimpleDateFormat
     */
    @Test
    public void test3(){


         // 方式一：预定义的标准格式。如：ISO_LOCAL_DATE_TIME;ISO_LOCAL_DATE;ISO_LOCAL_TIME
        DateTimeFormatter formatter = DateTimeFormatter.ISO_LOCAL_DATE_TIME;
        //格式化 日期 --->字符串
        LocalDateTime localDateTime = LocalDateTime.now();
        String str1 = formatter.format(localDateTime);
        System.out.println(localDateTime);
        System.out.println(str1);

        //解析：字符串 ---> 日期
        TemporalAccessor parse = formatter.parse("2021-02-17T13:28:46.09");
        System.out.println(parse);

        // 方式二：本地化相关的格式。如：ofLocalizedDateTime(FormatStyle.LONG)
        DateTimeFormatter formatter1 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.SHORT);
        //格式化
        String str2 = formatter1.format(localDateTime);
        System.out.println(str2);

        //本地化相关的格式。如：ofLocalizedDate
        DateTimeFormatter formatter2 = DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL);
        //格式化
        String str3 = formatter2.format(LocalDate.now());
        System.out.println(str3);

        //重点：  方式三： 自定义的格式。如：ofPattern(“yyyy-MM-dd hh:mm:ss”)
        DateTimeFormatter formatter3 = DateTimeFormatter.ofPattern("yyyy-MM-dd hh:mm:ss");
        //格式化
        String str4 = formatter3.format(LocalDateTime.now());
        System.out.println(str4);
        
        //解析
        TemporalAccessor accessor = formatter3.parse("2021-02-17 01:41:38");
        System.out.println(accessor);

    }


}
